TEA1755 - VOSENSE level during start-up sequence

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TEA1755 - VOSENSE level during start-up sequence

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randres
Contributor I

Hi. For TEA1755 controller at PFC start-up sequence. In the specification sheet and App Note (AN11142) one of the conditions is VOSENSE=1.1V.

Questions:

Will VOSENSE increase to 1.1V internally if there is no short circuit in pin 9 (VOSENSE)?

Or 1.1V is external coming from the voltage divider of VO(PFC), which also sets PFC output voltage?

I asked because in document UM10514 (Green Chip TEA1755DB1100 90 W power supply), power supply demo is rated at Vin=90 to 264VAC (page 6). 

Basing on the schematic (on pages 35 and 36), VOSENSE will not be 1.1V when Vin=90VAC or 127Vpk.

Also, TEA1755LT specification (Rev 1.1, page 2 ) is featured to have input of 70Vac to 276Vac I am thinking that VOSENSE=1.1V is internal provided VOSENSE pin has no fault condition.

Please advise. Thanks!

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1 Solution
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TomasVaverka
NXP TechSupport
NXP TechSupport

Hi Ronald,

 

I think the AN11142 provides the answer.

The OLP current source increases the voltage depending on the value of the resistor between VOSENSE and GND:

 

4.1.1.JPG

 

Best regards,

Tomas

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TomasVaverka
NXP TechSupport
NXP TechSupport

Hi Ronald,

 

I think the AN11142 provides the answer.

The OLP current source increases the voltage depending on the value of the resistor between VOSENSE and GND:

 

4.1.1.JPG

 

Best regards,

Tomas

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1,005 Views
randres
Contributor I

Hi Tomas, 

Thanks for your help!

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